/*
 * @(#)MD5.java   0.3-3 06/05/2001
 *
 *  This file is part of the HTTPClient package
 *  Copyright (C) 1996-2001 Ronald Tschal�r
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA 02111-1307, USA
 *
 *  For questions, suggestions, bug-reports, enhancement-requests etc.
 *  I may be contacted at:
 *
 *  ronald@innovation.ch
 *
 *  The HTTPClient's home page is located at:
 *
 *  http://www.innovation.ch/java/HTTPClient/ 
 *
 */

package org.everrest.http.client;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Some utility methods for digesting info using MD5.
 * 
 * @version 0.3-3 06/05/2001
 * @author Ronald Tschal�r
 * @since V0.3-3
 */
class MD5
{
   private static final char[] hex = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f',};

   /**
    * Turns array of bytes into string representing each byte as unsigned hex
    * number.
    * 
    * @param hash array of bytes to convert to hex-string
    * @return generated hex string
    */
   public static final String toHex(byte hash[])
   {
      StringBuffer buf = new StringBuffer(hash.length * 2);

      for (int idx = 0; idx < hash.length; idx++)
         buf.append(hex[(hash[idx] >> 4) & 0x0f]).append(hex[hash[idx] & 0x0f]);

      return buf.toString();
   }

   /**
    * Digest the input.
    * 
    * @param input the data to be digested.
    * @return the md5-digested input
    */
   public static final byte[] digest(byte[] input)
   {
      try
      {
         MessageDigest md5 = MessageDigest.getInstance("MD5");
         return md5.digest(input);
      }
      catch (NoSuchAlgorithmException nsae)
      {
         throw new Error(nsae.toString());
      }
   }

   /**
    * Digest the input.
    * 
    * @param input1 the first part of the data to be digested.
    * @param input2 the second part of the data to be digested.
    * @return the md5-digested input
    */
   public static final byte[] digest(byte[] input1, byte[] input2)
   {
      try
      {
         MessageDigest md5 = MessageDigest.getInstance("MD5");
         md5.update(input1);
         return md5.digest(input2);
      }
      catch (NoSuchAlgorithmException nsae)
      {
         throw new Error(nsae.toString());
      }
   }

   /**
    * Digest the input.
    * 
    * @param input the data to be digested.
    * @return the md5-digested input as a hex string
    */
   public static final String hexDigest(byte[] input)
   {
      return toHex(digest(input));
   }

   /**
    * Digest the input.
    * 
    * @param input1 the first part of the data to be digested.
    * @param input2 the second part of the data to be digested.
    * @return the md5-digested input as a hex string
    */
   public static final String hexDigest(byte[] input1, byte[] input2)
   {
      return toHex(digest(input1, input2));
   }

   /**
    * Digest the input.
    * 
    * @param input the data to be digested.
    * @return the md5-digested input as a hex string
    */
   public static final byte[] digest(String input)
   {
      try
      {
         return digest(input.getBytes("8859_1"));
      }
      catch (UnsupportedEncodingException uee)
      {
         throw new Error(uee.toString());
      }
   }

   /**
    * Digest the input.
    * 
    * @param input the data to be digested.
    * @return the md5-digested input as a hex string
    */
   public static final String hexDigest(String input)
   {
      try
      {
         return toHex(digest(input.getBytes("8859_1")));
      }
      catch (UnsupportedEncodingException uee)
      {
         throw new Error(uee.toString());
      }
   }
}
